Utilization of the Pilot-Scale Multistage Extractor for Removal of Zinc Ions with Central Composite Design Optimization; Case Study: Mass Transfer Rates

Abstract

In this work, the removal of zinc ions from aqueous solution by using a multistage extractor was studied. This investigation discusses the significance of the pilot-scale column, and it provides a brief overview of the potential of mass transfer rates for the extraction stage of Zn(II) with D2EHPA extractant. In the first step, the central composite design approach was performed to analyze the extraction behavior by the mass transfer coefficients. The optimization study showed that within the design variables, the significant parameter was the rate of agitation. The higher mass transfer coefficient increased the extraction rate due to more complex formation from aqueous to the organic phase. The optimum conditions were obtained as the rotation speed of 3.58 s^− 1, aqueous feed velocity of 0.75 mm.s^− 1, organic feed velocity of 0.89 mm.s^− 1. In the second stage, the experimental data were examined for the description of mass transfer behavior with the previous correlations. The results showed that reaction condition is a significant factor in the variation of mass transfer coefficients. The obtained data could be referred to in future improvement and applications of a multistage extractor for wastewater treatment and the removal of zinc ions.